Electrical musical instrument for producing bell tones



G. w. DEMUTH' 2,261,345

ELECTRICAL MUSICAL INSTRUMENT FOR PRODUCING BELL TUNES Nov. 4, 1941.

Filed Dec. 50, 1958 0 0 4 2 2 L? 1 J a V, P, G /h r=\ K H hm" F- J H a/ I 1 a "Z /5 0 1 m z 2 5.: z "a 1 1 a H W H 2 Zmpentor Galan W Eemuih (Iftomeg Patented Nov. 4, 1941 ELECTRICAL MUSICAL INSTRUMENT FOR PRODUCING BELL TONES Galan W. Demuth, Westville, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application December 30, 1938, Serial No. 248,542

2 Claims. (Cl. 116-148) This invention relates to electrical musical instruments for producing a bell-like tone, or what is more commonly designated as an electrical carillon. The device may be used to produce a single bell tone or a multiplicity of units of different pitch may be used to produce groups of bell tones or entire chromatic scales covering a very wide range.

It has heretofore been customary to use for the production of hell tones either actual bells or simulated bells or chimes. The simulated bells or chimes have usually been either an elongated hollow tubular member or a vibratable reed coiled into a circle or a spiral, the first form being customary in orchestral chimes, and the like, and the latter being more customary in clock chimes and similar devices. The coiled reed device has also been used in apparatus of the electrical type where a magnetic or electrostatic pickup is located adjacent the vibratable member and served to pick up the vibrations which are amplified by an electronic amplifier and thereafter reproduced by one or more loudspeakers.

Such prior art devices have been subject to a number of difiiculties in that they are extremely difilcult to tune, have a large number of.dissonant overtones interfering with the use of the several tones in chords and also interfering with recognizing the accuracy of tuning of the elements, and are difiicult to design for the reason that the exact dimensions and characteristics of their vibrating elements is dimcult to predict.

In the apparatus of the present invention, the vibrating element consists of a rod or wire preferably circular in cross section, substantially straight, and having a length which is great in.

relation to the diameter of the member. This rod is made of appropriate material, such as piano Figure 2 is a top view of the apparatus shown in Fig. 1.

- Referring first to Fig. 1, the vibrating member III, which may be of such length as to be tuned to practically any desired pitch within the ordinary range of musical instruments, may be made of piano wire preferably having a diameter of ..045 which is the most satisfactory value so far wire or tool steel, and is provided with an appropriate suspension, striking mechanism and. magnetic pickup.

One object of the invention is to provide an improved vibrating member for producing bell tones.

Another object of the invention is to provide an improved support for a tone producing vibrating member.

Another object of the invention is to provide an improved striking mechanism for devices for producing bell tones.

Another object of the invention is to provide an improved magnetic pickup for musical vibrators. v

Other and incidental objects of the invention reached for tones ,in the middle range, 1. e. for approximately two octaves above and below middle C although this size of the same material may be used considerably beyond this range and the invention is by no means limited to the use of either this material or material of this specific diameter. The diameter of the material to be used is determined largely by the amount of air damping which is desired. If very thin wire is used of, for example, half the thickness stated above, the relation between the energy in the wire after it is struck and the air damping is entirely different and the tone is damped out entirely too rapidly. With the dimension stated, the effect of the air damping decreases until the tone is suspended for a reasonably longtime.

Vibrating members of considerably greater diameter than that above stated may be used if proper supporting means are provided to prevent damping of the vibrations by the support. The crosssection of the vibrating member may be varied greatly from the circular cross-section stated, as for example, it might be rectangular, octangular or in other shapes, but material of circular cross-section is readily available and its orientation in the support is immaterial, while with material of varying cross-section the orientation of the rod in relation to the striking mechanism will produce a difierence in the resulting overtones due to different periods of vibration along different diameters.

The vibrating member [0 may be secured by swaging, soldering, welding or in other similar manner into the block ll. Soldering is preferred as it is rapid and simple and provides a sum ciently rigid attachment of-the vibrating member to the block. If the vibrating member isnot rigidly attached to the block it will not vibrate properly due to damping in the attachmentand the failure to provide sumcient reactance against willbe apparent to those skilled in the art from the elasticity of the vibrating member. The block substituted for this wire.

preferably a small brass cup of such weight as to ll may be attached to the heavier block l3 by means of a screw l2. This heavier block I3 is secured by the screws H to a metal plate II. The screws H pass through slots IS in which they are vertically adjustable. These slots ii are cut into a plate I! which may be of brass. and which. in turn, is supported on spring members I! which may be of steel or of phosphor bronze through which the member I5 is secured by bolts 20. It will be apparent that in this arrangement the vibrating member or members l0 reactv against the mass of the blocks II and I3 and the plate It. If either the block II, the block l3 or the plate I! were supported directly upon the wood frame oi. the instrument, considerable damping would result from the action of the frame material while the spring mounting just described prevents any such damping.

The framework or cabinet of the instrument is indicated at H and on this is supported a key bed I! which may be of wood, plastic composi: tlon, or the like, and to this key bed I3 the springs II are secured by appropriate screws. The block i3 is provided with a hole in which a tube 2|, which may be oi. brass, German silver, or similar material, is slidable and which may be secured in fixed position in the hole by set screw 23. The tube 2| carries adjacent its lower end a rod 23 of suitable permanently magnetizable material 33, such as hard steel or one of the alloys now on the market, such as Alnico, etc. A soft iron member 24 is attached to the end of the magand carries on its lower end a block 33 to which is attached a relt damper 39. This wire 31 is considerably more rigid than the wire 34 and may consist, for example, or a piece of piano wire .062" in diameter. When the key 23 is struck the wire 31 together with the block 33 and pad 38 urge the wire 34 forwardly toward the vibrating member ll, but when the key 33 strikes the pad 33 the block 33 is arrested and the hammer 35-36 swings forward. by its own momentum, striking the vibrating member ll a single sharp blow and then being retracted by the spring 33 into contact with the pad 33. When. the sprins wire 34 strikes the pad 33 its motion is damped and iurther vibration, such as a second striking of-the wire II, is prevented.

net 23 either by staking, riveting, or the like,

and this member 24, which is preferably flat so as to have a small dimension lengthwise of the vibrating member Ill, carries the pickup coil 25 from which connections are run to an appropriate electronic ampliiler. v

The striking mechanism includes a key, such as that indicated at 26, which is pivoted at 21, and which is urged toward its upper position by an appropriate spring 30. In the upper position this key may rest against a felt pad 3| carried by a wooden bridge 32 supported on the member l3. When the key is suddenly depressed, it strikes the felt pad 33 which is carried on the member ll.

The upper surface of the key carries a plate 33 to which the spring 33 is attached and this plate extends past the end of the key to carry the striking mechanism. The plate 23 carries a spring wire 34 which carries on its lower end the hammer 35-36. This wire 34 is preferably a piece of piano wire approximately .022" in diameter, and is soldered into the plate 39. It will be apparent, however, that a piece of any other desired type of spring material may be give proper momentum to the hammer when the key is struck and in this cup is fitted the striking member 36, which is preferably of hardwood, for most of the notes. This member 36 is provided, as shown in the drawing, with a chisel-like edge for striking the member I. at the desired point. On some notes, particularly the higher notes, it may be desired to strike the vibrating member III at a more precisely defined point and in thiscase a wire face may be placed across the front of the member 33.

To the rear of the member 34 a second wire member 31 is similarly soldered into the plate 23 The member 35 is" It will be apparent that the length oi. the vibrating member ll determines the pitch of the note which is sounded. The approximate length of the wire is readily determined, for example, by clamping a length of the wire in a vise and sounding it and then cutting the wire to length but allowing sumcient additional material for exact tuning. After the apparatus is assembled, exact tuning of the vibrating member I I is accomplished by grinding on the lower end to the proper point.

The exact point at which the wire is struck to produce the best tone quality is determined by loosening the screw 14 and moving the block l3 up or down in relation to the plate II. This point cannot be accurately predetermined as slight variations in the texture or hardness of the material of the vibrating element ll may produce great variations in the overtones produced and I have accordingly found it most desirable to adjust the striking point after the apparatus is assembled and the vibrating element is tuned. The position of the pickup element 34 is likewise adjustable by loosening the set screw 33 and sliding the tube 2| up or down in the block until it is located at such a point on the vibrating element that the most desirable tone or combination 0! tones is produced. l

The above described apparatus, when properly adjusted, will produce a bell tone which might be described as glass-like in quality as it has more or less the quality of a piece of glass when vibrated as distinguished from the clang including many discordant overtones which is characterir tie at many bells.

Having now described my invention, I claim:

1. Apparatus of the class described, comprising a vibratable element, substantially straight, hav-- ing a length great in proportion to its diameter, supporting means for said vibratable element consisting of massive supporting means for said element, means suspending said element substantially vertically from saidmassive means, and spring supporting means for said massive means.

2. Apparatus of the class described, comprising a vibratable element oi! hard magnetic material, substantially straight, having a length great in proportion to its diameter, supporting means for said vibratable element consisting of massive supporting means for said element, means suspending said element substantially vertically from said massive means, spring-supporting means for said massive means, and electromagnetic means supported from said massive means in cooperative relation to said vibratable element.

GALAN W. DEMUTH. 

